Fragment Shader not compiling on NVidia (it does on ATI)

Hi all,

A short description of my problem. I have a terrain generator which uses a certain vertex and fragment shader. It works completely as expected on my system, and that of 2 others with an ATI graphics card.
However, for another person with an NVidia card, the fragment shader fails at compilation (I have debugged my code and determined the compilation is really failing). However, without access to an NVidia card myself, I'm having a hard time figuring out what in the world could be wrong. I was hoping someone with NVidia experience could have a look at my shader code, and see if he/she can spot something "fishy". I will also present the vertex shader for completeness.

(As this is my first post, for some reason it isn't letting me post the shaders, even though they don't contain URLs or bad words, so here's a link to an online notepad: shrib.com/ekQlUonP)

...NVidia card, the fragment shader fails at compilation ... However, without access to an NVidia card myself, I'm having a hard time figuring out what in the world could be wrong. I was hoping someone with NVidia experience could have a look at my shader code, and see if he/she can spot something "fishy".

You can download the Cg distribution (Cg Toolkit Download link), and then compile the shaders using: